Nickel bis(stilbenedithiolate)

Nickel bis(stilbenedithiolate) or bis(dithiobenzil)nickel is a coordination complex with the formula Ni(S₂C₂Ph₂)₂ (where Ph = phenyl). It exists as a black solid that gives green solutions in toluene due to a strong absorption at 855 nm. The complex is a prototype of a large family of bis(dithiolene) complexes or the formula Ni(S₂C₂R₂)₂ (R = H, alkyl, aryl). These complexes have attracted much attention as dyes. They are of academic interest because the dithiolenes are noninnocent ligands.^[2] The lengths of the C-S and C-C bonds in the backbone, respectively 1.71 and 1.39 Å, are intermediate between double and single bonds.^[3]

Limiting resonance structures of a R₂C₂S₂M ring

Nickel bis(stilbenedithiolate)

Names
Other names bis[1,2-diphenyl-1,2-ethenedithiolato]nickel bis(dithiobenzil)nickel(II)
Identifiers
CAS Number	28984-20-5
3D model (JSmol)	Interactive image
ChemSpider	44211332
ECHA InfoCard	100.044.853
PubChem CID	5374634
CompTox Dashboard (EPA)	DTXSID5067427
InChI InChI=1S/2C14H12S2.Ni/c2*15-13(11-7-3-1-4-8-11)14(16)12-9-5-2-6-10-12;/h2*1-10,15-16H;/p-4/b2*14-13-; Key: LJISAPFYPQSNRX-DEWSNNOYSA-J
SMILES C1=CC=C(C=C1)/C(=C(/[S-])\C2=CC=CC=C2)/[S-].C1=CC=C(C=C1)/C(=C(/[S-])\C2=CC=CC=C2)/[S-].[Ni]
Properties
Chemical formula	C28H20NiS4
Molar mass	543.40 g·mol−1
Appearance	black-green solid
Density	1.466 g/cm3
Melting point	260 °C (500 °F; 533 K)
Structure[1]
Crystal structure	monoclinic
Space group	P21/n
Lattice constant	a = 0.5836 nm, b = 1.097 nm, c = 1.836 nm α = 90°, β = 91.4°, γ = 90°
Hazards
GHS labelling:
Hazard statements	H317, H334, H350, H372
Precautionary statements	P260, P270, P272, P280
Safety data sheet (SDS)	Bis(dithiobenzil)nickel(II). TCI
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The complex was prepared originally by treating nickel sulfide with diphenylacetylene.^[4] High yielding syntheses involve treating nickel salts with sulfided benzoin. The complex reacts with ligands to form monodithiolene complexes of the type Ni(S₂C₂Ph₂)L₂.^[5]